Progress towards 3D bioprinting of tissue models for advanced drug screening: In vitro evaluation of drug toxicity and drug metabolism

The drug discovery process is very long, costly, and challenging but essential in medical sciences. Advancements in new techniques to improve the efficacy of drug development are therefore needed. The 3D cell culture technique represents a step forward in studying human tissues and diseases, and developed in vitro 3D tissue models can be an excellent alternative to traditional 2D cell cultures and animal testing. They can replicate the physiological microenvironment of the living tissue-mimicking extracellular matrix (ECM), cell-cell/cell-ECM interactions, and the spatial cellular arrangement, thus such models are useful systems to evaluate better and comprehend drug responsiveness. The 3D bioprinting technique brings many advantages in the fabrication of 3D tissue models, such as custom-made microarchitecture, high-throughput capability, and co-culture ability. However, this technique has challenges related to cells and materials requirements as well as tissue maturation and functionality. This review introduces the leading bioprinting technologies (extrusion-based, inkjet-based and laser-assisted) and summarizes and discusses their applications to build organ models such as liver, intestine, cardiac, and tumor tissues for applications in drug discovery and drug toxicity studies. The different bioprinting approaches and 3D printed tissue constructs employed to evaluate drug dose-response and drug metabolism are critically reviewed and discussed.